Portable welding device

ABSTRACT

A substantially hollow supporting base made from a plastic material comprises an upper elongated supporting surface for the support of a plurality of plastic layers to be welded and a depressible pressure member cooperating with and movable relative to the supporting surface between a rest position and a welding position. An electric heating wire is connected to and extends along the elongation of the supporting surface for welding, in association with the pressure member, the plurality of plastic layers. All the other electrical components necessary for alternatingly heating the heating wire, are accommodated in the hollow interior of the supporting base.

United States Patent [72] Inventor Rolf Mayer Giengen, Germany [21]Appl. No. 884,200 [22] Filed Dec. 11, 1969 [45] Patented Nov. 30, I971[73] Assignee Robert Bosch I-lausgerate GmbI-I Giengen, Germany [32]Priority Dec. 14, 1968 [33] Germany [31 G 68 11 478 [54] PORTABLEWELDING DEVICE 10 Claims, 5 Drawing Figs.

[52] US. Cl 219/243,

, 156/515 [51] Int. Cl 1105b 1/00 [50] Field of Search 219/243;

[56] References Cited UNITED STATES PATENTS 3.106.630 10/1963 Klamp219/243 X 3,375,777 4/1968 Techtmann et al. 219/243 X FOREIGN PATENTS969,962 6/1950 France 219/243 1,307,307 9/1962 France 2l /243 PrimaryExaminerC. L. Albritton Attorney-Michael S. Striker ABSTRACT: Asubstantially hollow supporting base made from a plastic materialcomprises an upper elongated supporting surface for the support of aplurality of plastic layers to be welded and a depressible pressuremember cooperating with and movable relative to the supporting surfacebetween a rest position and a welding position. An electric heating wireis connected to and extends along the elongation of the supportingsurface for welding, in association with the pressure member. theplurality of plastic layers. All the other electrical componentsnecessary for alternatingly heating the heating wire, are accommodatedin the hollow interior of the supporting base.

PATENTEDNMOIBYI 3524.349

Ila 70b 20k FIG. 5

INVENTOR.

Roar H4960 BACKGROUND OF THE INVENTION The present invention relates toa portable welding device especially for use in households for fusing orwelding together a plurality of plastic foils, or analogous material, byheat and pressure.

Already known and available for quite some time are plastic bags usedfor the packaging of cold and/or frozen food articles, and the like, inorder to preserve and/or otherwise protect such packaged items.

Upon placing or enwrapping the articles in the plastic bag, the latter,usually, is hermetically sealed by heat and/or pressure sealing and isprovided with an easily severable corrugated seal, or any other type ofsuitable seal.

7 However, such sealing of the plastic bags, usually is done in the meatmarkets, supermarkets, and the like, but is never, or very rarely donein the home which, upon initial opening of the sealed plastic bags bythe consumer, presents the difficulty that the plastic bags, thusopened, cannot easily be resealed again and, therefore, such bags onlyare good for a one-time use. In addition, cleaning of such used bags isdifficult.

On the whole, this problem further exists in the household when articlesfor one reason or another, have to be hygienically and thus hermeticallysealed or wrapped in plastic or analogous material, and such covermaterial cannot be easily sealed simply for lack of a suitable homewelding device.

This situation is rather uneconomical and, in addition, makes the use ofsuch plastic bags relatively expensive.

SUMMARY OF THE INVENTION Object of the present invention is to overcomethe above disadvantages and to provide an electrically operated portablehome welding device especially adapted for use in households and whichpennits easy and hygienic packaging of a great assortment of food oranalogous articles and economical use of plastic or analogous material.

Such'a portable welding device adapted for welding or fusing a pluralityof layers of a plastic or analogous material comprises a supporting basemade from plastic material and which includes an upper supportingsurface for supporting a plurality of plastic layers to be welded, and apressure member cooperating with and movable relative to the supportingsurface between a first rest position and a second welding position. Anelectric heating wire for welding the plurality of fusible layers inassociation with the pressure member, is supported on and extends alongthe elongation of the supporting surface, and all the other electricalcomponents required for alternatingly heating the electric heating wire,are accommodated in the supporting base.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention-itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

' BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustratively shows aportable home welding device according to the present invention;

FIG. 2 shows an enlarged cross-sectional view of that part of theconstruction of the welding device of FIG. 1 located within the confinesbounded by the circle ll, FIG. 1;

FIG. 3 shows an enlarged cross-sectional view of a further part of theconstruction of the welding device of FIG. 1 located within the confinesbounded by the circle 111, FIG. 1;

FIG. 4 shows an enlarged cross-sectional view taken on line IV-IV, FIG.3; and

FIG. 5 shows a cross-sectional view taken on the line V--V, FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingsin which like reference numerals index like parts and with attentioninitially directed to FIG. 1, the electric welding device especially foruse in households for fusing or welding a plurality of fusible foils,such as plastic foils, according to the present invention is seen tocomprise a plastic housing 10 which accommodates all the requiredelectric components of the welding device, as will hereinafter bedescribed. The housing 10 essentially comprises a hollow base 10a and anarm 10b which projects laterally from one side of the base 10a and hasan overall substantially hollow U-shaped cross-sectional configuration.The upper portion 100 of the base 100 and the upper surface of the arm10b as such, together constitute an elongated support ledge 10b, c forthe fusible foils and the arm 10b has its free end, which is turned awayfrom the base 100, supported by a unitary support foot or leg 10d,disposed at the lower surface at this free end.

For simplification purposes, hereinafter reference will be made to thesupport ledge as being indexed with 10b, 0.

Extending along the elongation of the support ledge 10b, 0 and definedin part by the U-shaped profile of arm 10b, is a longitudinalsubstantially U-shaped groove l0e having an upwardly oriented open end,as clearly shown in FIG. 4. Accommodated in the U-shaped groove We is aU-beam 1] which is made of an electrically conductive material andwhich, with the longitudinally extending free lower ends of itsdownwardly orientated legs, rests upon the closed base or bottom 10f ofthe U-shaped groove 102. The base portion 11a of the U-beam 11 extendssubstantially level with the support surface of the support ledge 10b, 0and, at its upwardly orientated surface, is provided with aheat-resistant insulating strip 12 made of a material having a lowcoefficient of friction, e.g. polytetrafluoroethylene. The insulatingstrip 12 extends along the entire elongation of the U-beam 11 and issandwiched between the same and a heating wire 13 superimposed on thestrip 12 and the upwardly orientated surface of the base of the U-beam11 and with the axially opposite end faces of the heating wire 13downwardly bent behind the respective end faces of U-beam 11.

As shown in FIG. 3, one of the axially opposite end faces of the heatingwire 13 is anchored in a variable joint 14 at one end of the supportledge 10b, c. The variable joint 14 is axially adjustable relative tothe heating wire 13 by means of an adjustable screw member 15 which isrotatably mounted in the arm 10b and the free outer end of which extendsthrough and projects laterally from the arm 10b and is provided with aturnable knob 16 which permits manual adjustment of the tensile stressof the heating wire 13.

As shown in FIG. 2, the other of the end faces of the heating wire 13 isdownwardly bent at the other end of the support ledge and is connectedto the upper portion of an upstanding switch lever 17 which extends atthis end in the base 10a and is pivotably mounted therein at a pivotlocation 10g.

Riveted to the switch lever 17 is a bolt member 18 which, is unheated orswitched off condition of the heating wire 13, depresses and closes theon-contact 20 of an electric on-off switch 21 incorporated in theelectric primary circuit of an electric transformer 19. Engaging theswitch lever 17 with its one end and abutting against the end wall of aspring support 22 in the base [0a with its other end, is a pressurespring 220 which is operative to normally bias the switch lever 17 inoutward direction so as to disengage the bolt member 18 from theon-contact 20in order to release the same and to open the primarycircuit of the transformer.

The heating wire 13 is made of a material which has a high coefficientof thermic heat expansion and is incorporated in the electric secondarycircuit of the transformer 19 in the base 100.

As clearly shown in FIG. 2, a switch plate 23 is mounted above thetransformer 19 in the base 10a. Provided at the upper surface of theswitch plate 23 is a further switch member 24 which is electricallycoupled to the switch 21 and is provided with a movable contact tongue25. Arranged directly above thecontact tongue 25 in the base a, is adepressable button 26 which upon depression, starts or initiates thefusing or welding process of the welding device in that depression ofthe same and subsequent engagement of its lower end with the contacttongue 25, causes depression of the latter and engagement thereof withthe switch member 24. which connects the primary circuit of thetransformer 19 to a source of constant electrical energy, not shown. Theheating wire 13 incorporated in the electric secondary circuit of thetransformer 19, subsequently, is heated and expands along its entireelongation. During this expansion of the heating wire 13, the switchlever 17 under the spring tension of spring member 22a is pivoted aboutits pivot point 103 in direction away from the switch 21 which, as aresult, breaks the contact and opens the circuit between the bolt member18 and the oncontact 20 and thus disrupts the primary circuit of thetransformer l9. Simultaneously, the current supply to the heating wire13 is disrupted as a result of which the same cools and contracts andreturns to its initial starting condition, shown in FIG. 1. The switchlever 17, now returns to its initial position in which the bolt member18 again depresses and closes the on-contact 20.

By depressing the pushbutton 26 for a longer period of time, the weldingor fusing process is periodically repeated which suitably enables thefusing or welding of relatively thick foils.

In order to press the fusible foils against the heating wire 13, thewelding device is provided with a depressible pressure ledge 27 which ispivotably mounted about an axis on the upper portion of the base 10a andhas an overall configuration substantially matching that of the base 10aand the support ledge 10b, c. The pressure ledge 27 is movable between afirst rest position, shown in FIG. 1, and a second welding position, notshown, in which the same is moved toward the support ledge 10b, 0 toconfine the fusible layers between the inner pressure surface of thepressure ledge 27 and the support surface of the support ledge 10b, 0.

The pressure ledge 27 is connected to a cover plate 10h which closes theupper or foil-support side of the hollow base 10a, FIGS. 1 and 5, and isprovided with two parallel but spaced hinge hooks l0i interconnected byan axially extending bridge member 10k which also serves as a stopmember for the pressure ledge 27, as will presently be described.

The pressure ledge 27 is seen to be constituted by a plane section 27awhich is laterally bounded by and integral with two parallel spaced wallsections 27b each of which, at its inner end, is arranged with a movablepivot 270 each of which engages one of the spaced hinge hooks 10! on thecover plate 10h.

Arranged in a parallel plane with and adjacent the pivots 27c in section27a of the pressure ledge 27, is an elongated slot 27d in which atransparent illuminating ledge 28 is clampingly received. Theilluminating ledge 28 is seen to project through the wall of thepressure ledge 27 at the inner end thereof, and serves to limit thepivot movement of the pressure ledge 27 in direction away from thesupport ledge 10b, 0 by engaging the bridge and stop member 10k in thisdirection.

A pilot light or control lamp 29 is arranged beneath the illuminatingledge 28 in the base 10a and is incorporated in the electric circuit ofthe heating wire 13 and serves to indicate the hereinbefore describedon-and-off position of the switch.

Cooperating with the U-beam 11 in the support ledge 10b, 0, is astraight and substantially correspondingly shaped U- beam 30 connectedin the pressure ledge 27 and having the free lower ends 30a of itsdownwardly orientated legs inwardly bent so as to clampingly retain asubstantially correspondingly shaped rubber strip 31 having a protrudingflexible pressure surface 31a.

By depressing the pressure ledge 27, the pressure surface 31a of therubber strip 31 will abuttingly engage the U-beam 11 of the supportledge 10b, c, which support the heating wire 13.

To protect the rubber strip 31 and the fusible foils, the U- beam 11including the superimposed plastic strip 12 and the heating wire 13, isenclosed by a cover 32 made of a heat resistant unwettable plasticmaterial.

As shown in FIGS. 2 and 5, the pressure ledge 27 at its lower surface,is provided with a piston member 33 which, upon depression of the ledge27 in direction toward the support ledge 10b, 0, operatively engages thepushbutton 26, which, as already described hereinbefore, permits closingof the electric circuit of the transformer 19 and heating of the heatingwire 13.

A pressure spring 34 having its one end abutting against the cover plate10h of the base 10a and its other end abutting against the pressureledge 27, serves to return the latter into or retain the same in itsstarting or rest position in which the illuminating ledge 28 engages thestop member 10k of the cover plate 10h.

It will be understood that each of the elements described above or twoor more together may also find a useful application in other types ofwelding devices differing from the types described above.

While the invention has been illustrated and described as embodied inFIGS. 1 through 5, it is not intended to be limited to the detailsshown, since various modifications and structural changes may be madewithout departing in any way from the spirit of the present invention.

Without further analysis the foregoing will so fully reveal the gist ofthe present invention that others can be applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. A portable welding device for fusing a plurality of fusible layers,particularly layers of plastic material, comprising, in combination,support means comprising an upright base and an elongated arm portionprojecting laterally from said base and having a free outer end; anupright support member on said outer free end of said arm portion forsupporting said outer end; an elongated upper support face provided onsaid base and said elongated arm portion for supporting a plurality offusible layers thereon; pressure means mounted on said base movablerelative to said upper support face between a rest position and awelding position for engaging in said welding position a plurality offusible layers on said support face and for pressing the same againstsaid support face; and welding means associated with said upper supportface for heating said fusible layers pressed by said pressure means ontosaid support face so as to weld said fusible layers to each other.

2. A device as defined in claim 1, wherein said base, said elongated armportion and said upright support member are integrally connected to eachother.

3. A device as defined in claim 1, wherein said base and said armportion constitute a housing, and wherein said welding means areelectric welding means comprising an electric heating wire supported onsaid elongated support face for heating engagement with said pluralityof fusible layers, and electric circuit means accommodated in said baseand including switch means for periodically electrically actuating saidheating wire for heating the same and thereby said plurality of fusiblelayers.

4. A device as defined in claim 3, wherein said support face iselectrically nonconductive and has axially opposite ends and comprises agroove longitudinally extending between said opposite ends and supportmeans in said groove for supporting said electric heating wire, saidsupport means comprising a longitudinally extending electricallyconductive support beam having leg portions abutting the bottom of saidgroove and having an upper portion supporting said electric heatingwire.

5. A device as defined in claim 45 wherein said longitudinally extendinggroove in said support face has a substantially rectangularcross-sectional configuration, and wherein said longitudinally extendingsupport beam has a substantially inverted U-shaped cross-sectionalconfiguration, said upper portion of said support beam supporting saidelectric heating wire constituting the base portion of said beam andextending substantially level with said support surface.

6. A device as defined in claim 5, wherein said electric heating wire isprovided with thermoplastic insulating means comprising a first layersandwiched between said electric heating wire and said base portion ofsaid support beam and being heat-resistant and having a low coefficientof friction. and a second layer superimposed on said electric heatingwire and being heat-and-fluid resistant.

7. A device as defined in claim 6, wherein said electric heating wirehas opposite ends with one of said axially opposite ends adjustablemounted at one of said axially opposite ends of said support face, andwith the other of said ends electri cally connected to'said electricswitch means located in said base at the other of said axially oppositeends of said support surface.

8. A device as defined in claim 7, wherein said one end of said supportface adjustably mounting said one end of said electric heating wire, isprovided with manually operable adjustment means for varying the tensilestress of said electric heating wire, said adjustment means comprisingretaining means retaining said one end of said electric heating wire andan adjustable screw member abutting against said one end of said supportsurface and operative for displacing said retaining means relative tosaid one end of said support face in direction normal to the elongationof said electric heating wire.

9. A device as defined in claim I, wherein said pressure means ispivotably mounted on said base about an axis substantially parallel withthe elongation of said support face.

10. A device as defined in claim 3, wherein said pressure means ispivotally mounted on said base and having a lower pressure face of asize and configuration substantially identical to that of said supportface. and including a transparent member in said pressure means, pilotlight means on said base beneath said transparent member and in circuitwith said switch means to indicate actuation of said heating wire.

i I I i

1. A portable welding device for fusing a plurality of fusible layers,particularly layers of plastic material, comprising, in combination,support means comprising an upright base and an elongated arm portionprojecting laterally from said base and having a free outer end; anupright support member on said outeR free end of said arm portion forsupporting said outer end; an elongated upper support face provided onsaid base and said elongated arm portion for supporting a plurality offusible layers thereon; pressure means mounted on said base movablerelative to said upper support face between a rest position and awelding position for engaging in said welding position a plurality offusible layers on said support face and for pressing the same againstsaid support face; and welding means associated with said upper supportface for heating said fusible layers pressed by said pressure means ontosaid support face so as to weld said fusible layers to each other.
 2. Adevice as defined in claim 1, wherein said base, said elongated armportion and said upright support member are integrally connected to eachother.
 3. A device as defined in claim 1, wherein said base and said armportion constitute a housing, and wherein said welding means areelectric welding means comprising an electric heating wire supported onsaid elongated support face for heating engagement with said pluralityof fusible layers, and electric circuit means accommodated in said baseand including switch means for periodically electrically actuating saidheating wire for heating the same and thereby said plurality of fusiblelayers.
 4. A device as defined in claim 3, wherein said support face iselectrically nonconductive and has axially opposite ends and comprises agroove longitudinally extending between said opposite ends and supportmeans in said groove for supporting said electric heating wire, saidsupport means comprising a longitudinally extending electricallyconductive support beam having leg portions abutting the bottom of saidgroove and having an upper portion supporting said electric heatingwire.
 5. A device as defined in claim 4, wherein said longitudinallyextending groove in said support face has a substantially rectangularcross-sectional configuration, and wherein said longitudinally extendingsupport beam has a substantially inverted U-shaped cross-sectionalconfiguration, said upper portion of said support beam supporting saidelectric heating wire constituting the base portion of said beam andextending substantially level with said support surface.
 6. A device asdefined in claim 5, wherein said electric heating wire is provided withthermoplastic insulating means comprising a first layer sandwichedbetween said electric heating wire and said base portion of said supportbeam and being heat-resistant and having a low coefficient of friction,and a second layer superimposed on said electric heating wire and beingheat-and-fluid resistant.
 7. A device as defined in claim 6, whereinsaid electric heating wire has opposite ends with one of said axiallyopposite ends adjustable mounted at one of said axially opposite ends ofsaid support face, and with the other of said ends electricallyconnected to said electric switch means located in said base at theother of said axially opposite ends of said support surface.
 8. A deviceas defined in claim 7, wherein said one end of said support faceadjustably mounting said one end of said electric heating wire, isprovided with manually operable adjustment means for varying the tensilestress of said electric heating wire, said adjustment means comprisingretaining means retaining said one end of said electric heating wire andan adjustable screw member abutting against said one end of said supportsurface and operative for displacing said retaining means relative tosaid one end of said support face in direction normal to the elongationof said electric heating wire.
 9. A device as defined in claim 1,wherein said pressure means is pivotably mounted on said base about anaxis substantially parallel with the elongation of said support face.10. A device as defined in claim 3, wherein said pressure means ispivotally mounted on said base and having a lower pressure face of asize and configuration substantially idEntical to that of said supportface, and including a transparent member in said pressure means, pilotlight means on said base beneath said transparent member and in circuitwith said switch means to indicate actuation of said heating wire.